1. Field of the Invention
The invention relates to a heat radiation member and a method for manufacturing the same.
2. Description of Related Art
A technique in which, in order to efficiently radiate heat transmitted to a base material to the outside, irregularities are formed or high reflectance inorganic particles are disposed to a shape of a surface of the base material is known. For example, when the inorganic particles are disposed, a coat is formed on a surface of the base material, and the inorganic particles are dispersed in the coat.
As such a technique, heat radiation members such as shown below have been proposed. For example, in Japanese Patent Application Publication No. 2010-168998 (JP 2010-168998 A), a heat radiation member that includes a base material made of stainless, a nickel alloy or the like and a heat radiation coat coated on a surface of the base material is proposed. In the heat radiation coat that constitutes the heat radiation member, with an inorganic binder such as a glass binder or the like as a binder, inorganic particles constituted of an oxide made of at least one kind of manganese, iron, copper, cobalt and chromium are dispersed.
Further, as another technique, in Japanese Patent Application Publication No. 2004-43612 (JP 2004-43612 A), a heat radiation member in which a heat radiation coat is formed on a surface of a base material such as aluminum or the like is proposed. In the heat radiation coat that constitutes the heat radiation member, with a polymer resin as a binder, inorganic particles of an oxide of tin and, antimony are dispersed.
According to these techniques, inorganic particles made of a material (oxide) having reflectance higher than that of a material of the base material are dispersed in the heat radiation coat coated on a surface of the base material; therefore, heat transmitted to the base material can efficiently be radiated to the outside.
However, the heat radiation member described in JP 2010-168998 A uses a glass binder as an inorganic binder. Therefore, during deposition, a temperature of the glass softening temperature or more has to be used to deposit a heat radiation coat. As a result, when a metal material such as aluminum and the like having a melting point lower than the glass softening temperature for the base material, the base material may be melted. Further, when the heat radiation member is used in a temperature range of a temperature of the glass softening temperature or more, the heat radiation coat itself may deform due to softening of the glass binder.
On the other hand, the heat radiation member described in JP 2004-43612 A uses a polymer resin as the binder. However, during use of the heat radiation member, the polymer resin may degrade. Furthermore, due to thermal expansion difference between the polymer resin as the binder and a metal such as aluminum or the like that constitutes the base material, it is likely that thermal stress is generated in an interface of the base material and the heat radiation coat, and the heat radiation coat is peeled.